Revert "MacViews: Remove JavaScriptAppModalDialogCocoa"

This reverts commit 74d2ba14.

Reason for revert:

This breaks the dialog.

The beforeunload dialog *must* block all of Chrome. MacViews does not have the modality code do to so yet. If you implement that modality you may reland this.

Original change's description:
> MacViews: Remove JavaScriptAppModalDialogCocoa
> 
> Move from using Cocoa to using Views. The Cocoa version was was causing
> problems with app exit dialogs showing up in the wrong process in
> RemoteMacViews. This issue was solved by the views version.
> 
> Bug: 898604
> Change-Id: I30bd1e543fa98a1503d80b4ad3947f676eb5e0c6
> Reviewed-on: https://chromium-review.googlesource.com/c/1298300
> Commit-Queue: ccameron <ccameron@chromium.org>
> Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#605898}

TBR=ellyjones@chromium.org,ccameron@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 898604
Change-Id: I5ec60bc8490083175092da9b4f2d0a2167aac18a
Reviewed-on: https://chromium-review.googlesource.com/c/1331831Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607418}

chrome/browser/ui/BUILD.gn

@@ -2006,6 +2006,8 @@ jumbo_split_static_library("ui") {
       "cocoa/history_menu_cocoa_controller.mm",
       "cocoa/history_overlay_controller.h",
       "cocoa/history_overlay_controller.mm",
+      "cocoa/javascript_app_modal_dialog_cocoa.h",
+      "cocoa/javascript_app_modal_dialog_cocoa.mm",
       "cocoa/key_equivalent_constants.h",
       "cocoa/key_equivalent_constants.mm",
       "cocoa/keystone_infobar_delegate.h",
@@ -2067,7 +2069,6 @@ jumbo_split_static_library("ui") {
       "cocoa/window_size_autosaver.mm",
       "views/apps/chrome_app_window_client_views_mac.mm",
       "views/certificate_viewer_mac_views.mm",
-      "views/chrome_javascript_native_dialog_factory_views.cc",
       "views/dropdown_bar_host_mac.mm",
       "views/frame/browser_frame_mac.h",
       "views/frame/browser_frame_mac.mm",

chrome/browser/ui/cocoa/javascript_app_modal_dialog_cocoa.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_UI_COCOA_JAVASCRIPT_APP_MODAL_DIALOG_COCOA_H_
+#define CHROME_BROWSER_UI_COCOA_JAVASCRIPT_APP_MODAL_DIALOG_COCOA_H_
+
+#include <memory>
+
+#include "base/logging.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/macros.h"
+#include "components/app_modal/native_app_modal_dialog.h"
+
+class PopunderPreventer;
+
+namespace app_modal {
+class JavaScriptAppModalDialog;
+}
+
+#if __OBJC__
+@class NSAlert;
+@class JavaScriptAppModalDialogHelper;
+#else
+class NSAlert;
+class JavaScriptAppModalDialogHelper;
+#endif
+
+class JavaScriptAppModalDialogCocoa : public app_modal::NativeAppModalDialog {
+ public:
+  explicit JavaScriptAppModalDialogCocoa(
+      app_modal::JavaScriptAppModalDialog* dialog);
+  ~JavaScriptAppModalDialogCocoa() override;
+
+  // Overridden from NativeAppModalDialog:
+  int GetAppModalDialogButtons() const override;
+  void ShowAppModalDialog() override;
+  void ActivateAppModalDialog() override;
+  void CloseAppModalDialog() override;
+  void AcceptAppModalDialog() override;
+  void CancelAppModalDialog() override;
+  bool IsShowing() const override;
+
+  app_modal::JavaScriptAppModalDialog* dialog() const {
+    return dialog_.get();
+  }
+
+ private:
+  // Returns the NSAlert associated with the modal dialog.
+  NSAlert* GetAlert() const;
+
+  std::unique_ptr<app_modal::JavaScriptAppModalDialog> dialog_;
+  std::unique_ptr<PopunderPreventer> popunder_preventer_;
+
+  // Created in the constructor and destroyed in the destructor.
+  base::scoped_nsobject<JavaScriptAppModalDialogHelper> helper_;
+
+  bool is_showing_;
+
+  DISALLOW_COPY_AND_ASSIGN(JavaScriptAppModalDialogCocoa);
+};
+
+#endif  // CHROME_BROWSER_UI_COCOA_JAVASCRIPT_APP_MODAL_DIALOG_COCOA_H_

ui/views/widget/native_widget_mac.mm

@@ -302,11 +302,13 @@ void NativeWidgetMac::InitModalType(ui::ModalType modal_type) {
   if (modal_type == ui::MODAL_TYPE_NONE)
     return;
 
+  // System modal windows not implemented (or used) on Mac.
+  DCHECK_NE(ui::MODAL_TYPE_SYSTEM, modal_type);
+
   // A peculiarity of the constrained window framework is that it permits a
   // dialog of MODAL_TYPE_WINDOW to have a null parent window; falling back to
   // a non-modal window in this case.
-  DCHECK(bridge_host_->parent() || modal_type == ui::MODAL_TYPE_WINDOW ||
-         modal_type == ui::MODAL_TYPE_SYSTEM);
+  DCHECK(bridge_host_->parent() || modal_type == ui::MODAL_TYPE_WINDOW);
 
   // Everything happens upon show.
 }